Super long render times every time I edit

Hey all,

     I would really appreciate a quick response to this. Just for some background I am using PP Cs5.5 on a Macbook Pro with 8 GB of ram and am using .mp4 files.

     I have brought in an hour and a half long clip and I applied some color correction to it naturally it need to render and it took 7 hours to render. Now that it is finally rendered out every time i move the clip in the time line or make an edit it needs to take 7 hours to render every thing out again!

Please let me know if I am doing something wrong here or what it could be.

Thanks for the help.